1. Field of the Invention
The present invention relates to a recording and reproducing apparatus arranged to perform digital recording and reproduction of an audio signal, a video signal and the like.
2. Description of the Related Art
A recording and reproducing apparatus which is called "DAT (digital audio tape recorder)" has heretofore been known. In the recording and reproducing apparatus, an audio signal is digitally recorded and reproduced on and from a magnetic tape by using a rotary head.
Recently, for the purpose of copyright protection, a system for managing an information copying operation, which is called "SCMS (serial copy management system)", has been introduced into such a DAT.
This system is intended to impose a certain limitation on the operation of performing serial copying. In the SCMS, if a tape on which original information is recorded is referred to as "first-generation tape", copying of a digital audio signal from the first-generation tape to a "second-generation" tape is permitted, but copying of the digital audio signal to a "third-generation" tape, "fourth-generation" tape or later is inhibited.
However, since the above-described SCMS unconditionally imposes the limitation on the number of times of copying operations, a DAT user encounters the following problem in the case of a tape for which it is not necessary to impose any particular limitation on the number of times of copying operations, such as an original tape on which the DAT user himself has made a recording by using a microphone. For example, even if the DAT user desires to produce a plurality of copies of the third generation or later from his original tape to distribute them to other persons, he will be inconveniently inhibited from producing such copies.
Also, developments of digital VTRs arranged to perform digital recording of video signals have recently been in progress. If the SCMS is introduced into such a digital VTR, for example, the following problem will occur.
In general, a process for producing an original work by using a video camera-integrated type VTR includes the steps of making tape recordings of a multiplicity of materials by using a video camera and a microphone, then assembling and editing the tape-recorded materials to prepare a tape of the second generation, then adding music, such as BGM (background music), to the tape, and finally performing predetermined processings such as mixing-down of the sound recordings, thereby finishing the original work in the form of a recording made on a tape of the third generation.
Accordingly, although in the simplest process it is possible to finish the work on the second-generation tape, it is commonly necessary to make tape copies of up to at least the third generation. If the quality of the work is to be further improved, it is necessary to make a tape copy of the fourth generation or later. However, if the tape copy of the fourth generation or later is to be prepared, the SCMS will serve as a very inconvenient system.